Prevalence And Related Factors Of Arrhythmias In Patients With Hypertrophic Cardiomyopathy

Background Patients with hypertrophic cardiomyopathy (HCM) commonly associated with a variety of arrhythmias, including atrial fibrillation (AF),ventricular arrhythmias and bradyarrhythmia. Disorganized cellular architecture, myocardial ischemia, myocardial scarring and expanded interstitial collagen probably served as substrates and predisposing factors of life-threatening arrhythmias in HCM.Objective We aim to explore the incidence and risk factors of AF, dangerous ventricular arrhythmias and bradyarrhythmia in patients with HCM, and improve the awareness of clinicians on HCM associated with life-threatening arrhythmias.Methods We retrospectively collected the clinical data of86unrelated patients diagnosed as HCM in our hospital from January2009to January2012,including each patient’s personal characteristics, clinical manifestations,echocardiography,12-lead electrocardiography(ECG),24h Holter ECG monitoring, coronary angiography, left ventricular angiography and related treatment.Results1.In86patients with HCM,male and female patients were56and30, respectively, and mean age was58.4±14.3years.2.21patients (24.4%) had documented AF,7patients with paroxysmal AF and14patients with chronic AF.72patients(85.7%) had premature ventricular contractions (PVCs),36patients (41.9%) had PVCs with Lown graded3, and20patients (23.3%)had non-sustained ventricular tachycardia (NSVT).8patients (9.3%)had sick sinus syndrome (SSS),11patients (12.8%) had atrioventricular block (AVB) and9patients(10.5%) had atrial fibrillation with slow ventricular rate and long RR interval (RR interval>2.0s).3.The mean age at examination was64.1±11.0years in patients with AF, older than those with sinus rhythm (56.6±14.8years)(p=0.037). Left atrial diameter (LAD) was greater in patients with AF than those without AF (45.3±5.2mm vs40.2±5.2mm)(p<0.01). There were8cases (38.1%)in NYHA class III and IV in AF group, more than those without AF (6.2%, p=0.001). And left ventricular ejection fraction (LVEF) in AF group was lower than those without AF (64.8±9.7%vs69.4±8.1%,p=0.036).4.Maximum left ventricular wall thickness (MLVWT) and LAD was greater in patients with dangerous ventricular arrhythmias (B group) than in patients without dangerous ventricular arrhythmias (A group)(23.1±5.4mm vs20.2±4.9mm and42.8±5.2mm vs40.4±5.8mm, p=0.009and0.048,respectively).The incidence of AF in B group was significantly higher than in A group (36.1%vs16.0%, p<0.05).5.In patients with pacemaker implantation, the age (mean67.6±7.4years) was older than those without pacemaker implantation (mean55.5±14.1years, p=0.01).LVEF in patients with pacemaker implantation was significantly lower than in patients without pacemaker implantation (64.0±10.0%vs69.3±8.1%,p=0.024).And the incidence of AF in patients with pacemaker implantation was significantly higher than in patients without pacemaker implantation (52.9%vs17.4%,p<0.05).Conclusions Our study showed the incidence of arrhythmias in patients with HCM, including AF, dangerous ventricular arrhythmias and bradyarrhythmia, was quite high. And the incidence of AF and bradyarrhythmia was positively correlated with age increasing. The occurrence of AF was significantly associated with LAD,cardiac dysfunction and age. The prevalence of dangerous ventricular arrhythmias was41.9%, and its occurrence was associated with MLVWT and LAD.LVEF was significantly decreased in patients with pacemaker implantation.The prevalence of AF in patients with dangerous ventricular arrhythmias and bradyarrhythmia was much higher than others without dangerous ventricular arrhythmias and bradyarrhythmia. Therefore, AF might play an important role in the prognosis of HCM patients.